The project for the coming year will deal with the isolation of the subunit protein components of yeast and beef heart cytochrome oxidase. The subunits will be characterized chemically and antisera will be prepared against the purified proteins. The antisera will be used as probes for partial functions of cytochrome oxidase. The following parameters will be studied. Inhibition of cytochrome oxidase activity. The possible abolition of the spectral differentiation between cytochromes a and a3. Inhibition of the binding of cytochrome c to the enzyme. Finally, the antisera to the various subunits will be tested on energized functions of reconstituted cytochrome oxidase membranes, such as ion transport. These experiments should provide new clues about the function of the various subcomponents of cytochrome oxidase.